1. Field of the Invention
The present invention relates in general to an office chair arm rest and in particular to an office chair arm rest that can be adjusted in height and rotation about a vertical axis.
2. Description of Related Art Including Information Disclosed Under 37 C.F.R. xc2xa7xc2xa71.97 and 1.98
There are many different patents disclosing chair arm rests that can be adjusted vertically in height and rotationally in a horizontal plane to conform to the arms of the user of the chair.
Some of these patents disclose hydraulic actuators for raising and lowering the arm rest, such as U.S. Pat. Nos. 5,931,536; 5,908,221; and 5,765,804.
Others disclose some manually-activated support shafts that can be manually raised and lowered with some type of engaging device. Some of such patents are U.S. Pat. Nos. 5,393,124; 5,971,484; 6,053,578; 5,895,095; 5,749,628; 5,641,203; 5,647,638; and 5,407,249.
Other patents disclose strictly horizontally-adjustable arm rests such as disclosed in U.S. Pat. Nos. 5,590,934; 5,655,814; 5,884,976; 5,944,486; and 6,045,191.
All of these patents disclose complex mechanisms for raising and lowering the arm rest and for pivoting the arm rest in a horizontal plane.
It would be in a desirable to have an arm rest that can be moved both in the vertical plane and rotated horizontally with simple mechanisms that are easily constructed and easily usable.
The present invention relates to a height and pivot-adjustable office chair arm assembly that is operated vertically to provide different arm rest heights using a gas cylinder and is rotated in a horizontal plane about a vertical axis using a simple radially-biased ball bearing and detent assembly that is operable independent of the mechanism for raising and lowering the chair arm rest.
The chair arm assembly has an arm rest assembly thereon and comprises an arm support having one end for attaching the chair arm assembly to a chair and having an opposite end. A gas cylinder cooperates with the arm support for movement in the vertical direction to raise and lower the arm rest assembly to any selected vertical position. A shroud surrounds and vertically moves in relation to at least a portion of the arm support and has an upper end. The shroud is connected to the gas cylinder for vertical movement by the gas cylinder and an arm rest pivot support attached only to the shroud receives the arm rest assembly and enables the arm rest assembly to pivot in a horizontal plane thereby allowing the arm rest to assume a selected rotational position independent of the operation of the gas cylinder mechanism.
The shroud is formed of a hollow tube that slidedly receives the arm support. It has a cross-sectional shape that conforms to the cross-sectional shape of the arm support and is such that the shroud can move vertically with respect to arm support but is non-rotatable with respect to the arm support. In the preferred embodiment, the cross-sectional shape of the shroud and the arm support are ovate.
The arm rest assembly itself has an upper arm pad assembly for receiving the arm of the user, and a lower arm pad assembly that has a first end attached to the upper arm pad assembly, and a second end having a bearing and ring assembly that is associated with the arm rest pivot support that is attached only to the shroud. There is a detent carrying device fixedly attached to the lower end of the shroud to mate with the bearing support ring and assist in holding the arm rest in a given horizontal rotational position. The detent carrying device matingly engages the at least one bearing and spring assembly to enable the bearing to rotatively move from one detent to another as the arm rest pivot support plate is rotated about a substantially vertical axis to establish a given rotational position of the arm rest.
The novel detent-carrying device has a plurality of vertically-oriented detents and there are at least one bearing and spring assembly on the lower arm pad assembly such that each of the bearings radially engages a different one of the detents for releasably holding the arm rest in a given rotational position. In the preferred embodiment, the bearings are ball bearings biased radially against elongated vertically-positioned detents by springs or other resilient devices. The bearings could also be roller bearings that would also be biased radially against the detents by the springs. In the preferred embodiment, at least two sets of three detents are disposed on diametrically-opposed sides of the shroud, and each of the at least two bearings radially and releasably engages a corresponding set of detents. The top of the shroud is circular with an outer periphery for carrying the vertically-oriented detents. The bearing and spring assemblies are spaced from each other with each of the bearings releasably and radially engaging corresponding detents and enabling the arm rest assembly to assume any selected horizontal position represented by the detents. In the preferred embodiments, the detents allow 40xc2x0 rotation of the arm rest assembly.
Further, the novel arm rest assembly comprises a substantially V-shaped arm pad assembly having first and second legs joined at one end. The first leg forms a substantially-horizontal upper rest for the user""s arm, and the second leg is a lower rest for attachment for the shroud upper end, and the first leg is longer than the second leg.
In the preferred embodiment, the second leg is at least partially hollow with a lever actuator extending from the hollow portion of the second leg engaging and operating a lever extending through the partially-hollow second leg between the lever actuator and the gas cylinder such that the lever actuator can be used to move the lever to actuate the gas cylinder and enable raising and lowering of the arm rest assembly.
Thus, it is an object of the present invention to provide an arm rest for a chair that can be adjusted both vertically and rotationally in the horizontal plane about the vertical axis for adapting to a particular user.
It is also an object of the present invention to provide an arm rest assembly that is adjustable in the vertical direction with the use of a gas cylinder, and in the horizontal rotational position by a bearing radially biased against the detent assembly.
It is still another object of the present invention to provide a chair arm rest assembly that is movable in a vertical direction with a gas cylinder having an upper end attached to a shroud surrounding an arm support in which the gas cylinder can move vertically with the cross-sectional shape of the shroud and the arm support being such that the shroud can move vertically with respect to the arm support but cannot be rotated.
It is another object of the present invention to provide the shroud and the arm support with a cross-sectional ovate shape to allow sliding vertical relative motion but to prevent horizontal rotation with respect to each other.
It is also an object of the present invention to provide an arm rest assembly that has substantially V-shaped arm pad assembly having first and second legs joined at one end with the first leg forming a substantially-horizontal upper rest for the user""s arm and the second leg forming a lower rest for attachment to the shroud upper end with the first leg being longer than the second leg.
Thus, the present invention relates to a height and pivot-adjustable office chair arm assembly having an arm rest assembly thereon and comprising an arm rest support having one end for attaching the chair arm assembly to a chair and having an opposite end; a gas cylinder cooperating with the arm rest support for movement in the vertical direction to raise and lower the arm rest support to any selected vertical position; a shroud surrounding and vertically movable in relation to at least a portion of the arm support and having an upper end; the shroud being connected to the upper end of the gas cylinder for vertical movement; and an arm rest pivot support attached only to the shroud for receiving the arm rest assembly and enabling the arm rest assembly to pivot in a horizontal plane thereby allowing the arm rest assembly to assume any selected rotational position.